1. Field of the Invention
The invention relates to a method for communicating with an object, and to a module used by the object. The method can for instance be used for observing and/or localizing objects.
In the first place the invention serves to localize stolen objects, particulary vehicles, such as cars and trucks.
More generally the invention is applicable for also localizing objects other than vehicles, such as valuable pieces of art, stolen or not.
In the second place, the invention permits communicating with vehicles, for instance for deactivating or immobilizing them at the request of the owner, the official authorities, an insurance company etc. or activating attention attracting means such as an alarm.
In the third place the method can be used for observing vehicles e.g. in toll traffic systems.
2. Discussion of Related Art
Several systems are available or will become available shortly for these purposes.
An overview of the systems is found in the following table 1 and can be divided in four different types as set forth after table 1.
TABLE 1 Overview of Existing Localization and Signalization Systems Principle Area of Acc. of Name Purpose Operation Mode When Origin (m) Oper. CARANGEL L GPS + GSM/MTEX A Now Netherlands 25 Europe XC REFINDER L GPS + GSM A Now Netherlands 20 Europe QUICKTRACK L Ground system A ? Australia 50 Netherlands SPY L GPS + GSM/MTEX A ? USA 25 Netherlands MOBITRACER L GPS + GSM A 1996 Netherlands 25 Netherlands SATSTING L GPS + GSM/MTEX A Now Canada 25 Canada STARSYS L Satellite A 1997 USA & &gt;500 worldwide France TRACKER L Ground system P Now USA 25-100 (regional) NUSAFE L GPS + GSM A 1996 Germany 25 Europe ALCATEL L GPS + GSM A ? Germany 100 Europe TRAKBAK L Ground system A 1996 UK 25 Netherlands & UK SATCON L Satellite A 1999 Germany 10-50 worldwide SKEYE L GPS + GSM A 1996 Germany 10-25 Europe CEL TRAK L GPS + ATF3 A 1996 Ireland 10-25 Netherlands NIGHTWATCH L Ground system A 1996 UK 10 UK CLOS L GPS + GSM A ? Netherlands 10-25 Europe SERPISPACE L GPS + GSM A 1996 Italy 10-25 Europe DETVOL S induction P 1997 France 15 France VOLBACK S induction A Now France -- France FORD/MOTOROLA D Paging P 1997 Belgium -- Benelux SPOOKY D Paging P 1996 Belgium -- Benelux
1. Signalization systems: these systems can only signal that a vehicle with the module installed, has passed a certain beacon. The permanent localization of such a system is impossible. In table 1 these systems are marked with the letter "S" in the Purpose column.
2. Localization systems: these systems permit permanent localization of the vehicle in which the module is installed. Most of these systems have a data link over which the localization parameters are sent to a service center. These systems are active or passive.
Active systems place a call to the service center when the vehicle is the subject of criminal intervention. PA1 Passive systems rely on the owner of the vehicle calling the service center or a help desk.
The mode of the system is indicated by either a capital "A" or "P" in table 1.
The passive systems have the disadvantage that between the moment of criminal intervention and the placement of the call from the owner valuable time can get lost. In table 1 these systems are marked with the letter "L" in the Purpose column.
Such systems are described amongst others in FR 2,718,532 and "Tracking en Tracing systemen speuren gestolen auto's op" from T. A. Koopmans, periodical "Preventie", January 1996, issue 149, The Netherlands.
3. Deactivation systems: these systems permit the owner of the vehicle once a theft is noticed, to deactivate his car by means of a telephone call. In table 1 these systems are marked with the letter "D" in the Purpose column.
4. Tall traffic systems: these systems allow automatic taxation of passing vehicles. In table 1 these systems are marked with the letter "T" in the Purpose column.
In the described localization systems, most of them make use of GPS satellites to do an exact localization and use the Global System for Mobile communications (GSM) to communicate this exact localization towards what can be called a service center. One disadvantage of this type of system involves reception of the GPS satellite signal. GPS signals are high frequency signals and are very directional in nature. This causes signals to get lost in between higher buildings and constructions. Since they are satellite transmitted, the signals that reach the Earth's surface are very weak and can not penetrate any material.
The GPS satellites are owned and operated by the army of the United States of America. During times of crisis, the accuracy of the transmitted signals can be made much less than the normal accuracy. This to prevent "the enemy" from using one's own satellites.
Since the system is being used on a fairly regular basis in several civilian applications, there exist plans to turn the system into a subscribed system for which Europe has to pay a certain license fee to the USA, making future applications subject to financial consequences.
Despite the fact that the GSM network is more reliable and independent than the GPS system, it is not being used for localization in any of these systems. However, its accuracy is much less when no other localization parameters are available.
The price of most of the systems in table 1 is set mostly by the price of exploitation of the communication. Even with the current GPS situation in which reception is still free, the GSM communication can not be switched off but is in a permanent stand by status. Since its function can then be compared with a normal GSM mobile phone the subscription fee is the same.
Furthermore, any system that uses the GSM component in a continuous stand by or active state, will generate a lot of handover protocol overhead. Such systems are bound to fail when used in large volumes since the current GSM networks would become swamped with protocol communication blocking any other useful data traffic.
The systems that use proprietary data communication protocols like MOBITEX, ATF3 and the like all depend on the roaming agreements between the several network providers of these systems. These systems are mostly restricted to the national borders of those countries that are serviced by these operators.
Systems that make use of ground based infrastructure, like Tracker, Trakbak, Quicktrack and Nightwatch are inherently bound by the area that is covered by the infrastructure. Mostly, these systems operate on the principle that the signal of several transmitters is fed into a trigonometrical algorithm that results in localization. The most obvious disadvantages of these systems are that the area of operation is limited and that the infrastructure and the support and maintenance of the infrastructure is not very cost effective when operated over a large area for a single specific application.
Another observation that can be made about the above mentioned known systems and also about other systems as described in U.S. Pat. No. 4,651,157, U.S. Pat. No. 5,276,728, EP 87302967 and DE 43 04 094 as an example, is that none of these systems encrypts the communication. If these systems use a cellular communication network, the only encryption is done inside the protocol of this network. No additional privacy or safety precautions are taken.
The above mentioned systems are not aimed at integration with the multiplexed bus systems. The logical consequence of this is that the communication safety with other components in the vehicle is non existing.
U.S. Pat. No. 5,357,561 describes a method for communicating with an object in which two networks are used, the first one being a paging network and the second one a cellular mobile communication network. For several applications the use of only these two networks is not sufficiently reliable.